Abstract:
Based on external and internal morphology, osteology and morphometries
the seven species of Paralonchurus Bocourt are grouped into two subgenera,
Paralonchurus and Polyclemus. The monotypic Ionchurus Bloch was more
similar to P. elegans and P. petersi than to P. brasiliensis, P. dumerili, P. goodei,
P. peruanus and P. rathbuni in most of the characters investigated.
The relationships among the species of Paralonchurus and L. lanceolatus
are determined on the basis of mental pores, mental barbels, snout pores,
external morphology, swim bladder and its muscular anatomy, jaw muscles
and osteology. The morphology of retractor arcum branchialium (RAB),
lower jaw muscles and pharyngeal skeletons are used to demonstrate the
relationships of Paralonchurus and Lonchurus to other euteleostean fishes.
Both genera possess primitive eusteleostean characters.
